This invention relates to improvements in seaming rollers for automated canning machinery; more specifically, this invention relates to an adjustable, locking pin for seaming rollers.
Seaming rollers are used in automated machinery for packaging foods and the like in metal cans. In assembling a can, typically the top and bottom can lids are affixed to a generally cylindrical can body. The sheet metal along the rim of the can body is forced outward and somewhat downward to form a lip. A generally circular disc of similar material, which will form the can lid, is bent downward about its outer periphery to form a circular flange. The can lid is placed over the can body and the flange of the can lid is forced inward and upward to extend between the can body and the lip. The can body lip and the can lid flange are then pressed together, sometimes with a gasket material interleaved between the flange and the lip, to form an asceptic seal or seam which is both air-tight and leak-proof.
The operations for sealing can lids to can bodies are performed by pressing the lid and body against rotating dies generally referred to as seaming rollers. Each seaming roller typically has one or two types of die surfaces, one for forcing the flange into position between the can body and the lip, and a second die surface for pressing the can lid and can body together to form the seal.
Typically, seaming rollers include a spindle which can be mounted to the canning machine and a generally ring-shaped body rotatable on bearings about the spindle. The appropriate die surfaces for sealing can lids to can bodies are defined along the periphery of the rollers. A typical automated canning machine seals several cans at once by utilizing twelve or more seaming rollers, adapted to the particular size and type of can being used.
Each seaming roller on a canning machine must be closely positionable against the flange of the can lid within a very small tolerance to assure formation of an acceptable seam. The die surfaces of the seaming roller body should be freely rotatable and held against the can lid flange without deviating in any direction by more than about 0.001 inch (0.025 mm). To maintain the roller body in proper adjustment, the positioning and alignment of the bearings and the roller body with respect to the spindle are critical. The roller body and the bearings must be adjustably positionable with respect to the spindle so that the roller body is freely rotatable about the spindle. At the same time, float between the bearings must be substantially eliminated so that the roller body rotates with little or no deviation from the axis of the spindle.
In a typical canning machine, the seaming rollers must be replaced relatively frequently. Each different size and type of can generally requires a different size seaming roller. In addition, even under otherwise optimal conditions, the seaming rollers and die surfaces wear and must be replaced after being used to seal approximately one million cans. The alignment, positioning, and rotation of the roller body of each seaming roller must be checked and adjusted each time the seaming rollers are replaced. In known seaming rollers, this is a very time-consuming and, therefore, costly process.
For maximum life of the individual seaming rollers, the roller bodies and the bearings must be properly positioned to substantially eliminate any float between the bearings and thus any wobble of the roller body on the spindles. In addition, to maximize the useful life of the bearings, the bearings must be greased; the grease used is edible and non-toxic to avoid dangerous contamination of the contents of the cans. Since the roller bodies are in continual motion during operation, it is highly desirable to apply the grease to the roller body bearings through the generally stationary spindle.
Several devices and arrangements intended to accurately position the roller body and the bearings with respect to the spindle are known. Each of these will be described and discussed below in conjunction with the detailed description of the preferred embodiment of the present invention. For various reasons, each of these prior devices or arrangements has proved unsuccessful or inconvenient and undesirable for use.